1. Field of the Invention
The instant disclosure relates to a recognition system; in particular, to a recognition system having a periodic guided-wave structure.
2. Description of Related Art
Radio frequency identification system (RFID system) is widely utilized to automation circumstances, such as a warehouse management, the mass production process or a transportation payment system. The RFID system may include a RFID reader and at least a RFID tag. On some conditions, it is better for the RFID reader to be designed to recognize more RFID tags.
Traditionally, the near field antenna of the RFID reader may produce vertical polarized magnetic field and horizontal polarized magnetic field, and the strength of the magnetic field (vertical polarized or horizontal polarized) varies due to the design manner of the near field antenna. Thus, the traditional near field antenna may be designed to recognize all of the RFID tags in a pre-defined reorganization area. For example, the RFID tags in different position or different direction relative to the RFID reader.